/*
 * Copyright (c) 2024 Oracle and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.helidon.tracing;

import java.util.Optional;
import java.util.Set;

/**
 * Behavior common to all baggage implementations.
 */
public interface Baggage {

    /**
     * Returns the value for the specified baggage key.
     *
     * @param key key for the value to retrieve
     * @return {@link java.util.Optional} of the value for the key; {@link java.util.Optional#empty()} if absent.
     */
    Optional<String> get(String key);

    /**
     * Returns the keys present in the baggage.
     *
     * @return set of key names; empty if none.
     */
    Set<String> keys();

    /**
     * Returns whether the specified key is present in the baggage.
     *
     * @param key key name to check
     * @return true if the baggage contains an entry for the specified key; false otherwise
     */
    boolean containsKey(String key);
}
